This invention relates to indexing systems for text material.
Textual material, such as government statutes and regulations, is frequently organized by "logical" categories of related subject matter and numerically subdivided. For example, a body of regulations may be organized and numbered in categories corresponding to the individual executive agencies of the government and each of these numerically subdivided according to the specific subject jurisdictions or applications the agency is authorized to administer. When information, such as statutes and regulations, changes frequently and is widely and frequently consulted, it becomes desirable to provide means for indexing the various categories and subcategories so that the information in any particular category or subcategory may be more readily available and easily accessible. When a body of information, such as regulations, in printed form is releasably bound, such as in a loose-leaf binder, indexing is frequently accomplished by providing tabbed dividers between categories. These serve to separate and distinguish the categories and make it easier and quicker for a user of the collection of information to open the bound material to the category of interest. It is common practice to locate the tabs of each divider in such a fashion that they present a staggered array along the outer edge of a page of print. Typically, this staggered array of tabs is in no special order nor are the tabs within the array of special dimension.
Given these circumstances, when the assembly of material contains a large number of categories or subcategories or when the categories or subcategories are frequently changed, as by deletion of some categories and addition of others, disorder of the array is created and the benefits of logical tabbing are lost or greatly diminished. For example, when it is desired to insert a new tabbed category of similarly aligned information into the middle of a body of existing material which previously had been tabbed in a fixed array, the tab location necessarily must be arbitrary. Thus a tab position results which does not conform with the previously established order of the array and thus misrepresents the relative position and significance of the new category of material in the context of the other preexisting categories. When this is repeated as a consequence of frequent changes, the logic of the total organization of the assembly of information is lost and the disarray creates confusion and difficulty in any search for information within the assembly. To preclude this situation, the organizer of the material must periodically realign and remake the index tab system at great cost to the producer and at considerable inconvenience to the user.
U.S. Re. Pat. Nos. 12,446; 675,909; 790,002; 1,084,449; 1,294,043 and 1,824,659 are representative of prior art indexing systems for indexing releasably bound assemblies of textual material. Such systems provide means for accessing textual material organized in hierarchical fashion. In such systems, however, it is not possible to change by adding or deleting categories of material in the central portion of the assembly without disturbing the order of the system.